Systems and methods for activating a circuit of an implant device

ABSTRACT

The present disclosure relates to systems and methods for activating a circuit of an implant device. Consistent with one implementation, an implant device is provided with a sensor including a working electrode (WE) and a counter electrode (CE). The sensor may be configured to generate a first current at the CE when the implant device is implanted in a body of a subject. A sensing circuit may also be provided that is electrically coupled to the WE of the sensor. The sensing circuit may be activated based on the first current and utilize the sensor to measure one or more parameters of an individual or other subject.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Pat. Application No.16/561,911 filed Sep. 5, 2019, which is a divisional of U.S. Pat.Application No. 15/699,471, filed Sep. 8, 2017, now U.S. Pat. No.10,448,833, issued Sep. 8, 2017, which claims priority to U.S.Provisional Pat. Application No. 62/397,582, filed Sep. 21, 2016, theentirety of each are hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure generally relates to systems and methods foractivating a circuit of an implant device. More specifically, andwithout limitation the present disclosure relates to systems and methodsfor activating a circuit of an implant device with power from a batteryor other source in response to detecting that the device has beenimplanted in a body of an individual or other subject.

BACKGROUND

A wide variety of implant devices exist today for various applicationsand uses. For example, an endoscopic capsule may be implanted to performtelemetry within the gastrointestinal tract of a patient. As anotherexample, a brain-computer interface may be implanted to augment and/orrepair various cognitive and sensory-motor functions. As a still furtherexample, implanted micro sensors may be utilized for sensingphysiological parameters of an individual. These and other implantdevices may include various subsystems for collecting data, providingoutputs based on collected data, performing calculations, and/orcarrying out various instructions.

Implant devices are often small in size and/or include integratedcomponents. Therefore, accessing, replacing, and/or rearranging theinternal components of an implant device can be challenging orprohibitive. For example, it may be difficult to replace or rearrangecomponents because some of the internal components are encapsulated withsealant at the time of manufacture. As another example, altering orchanging internal components may be difficult because the handling ofthe components requires complex, expensive equipment and/or techniquesthat may not be available or known to those other than the manufacturer.As a result, the internal components of implant devices, including thebattery, are typically fully assembled and wired at the time ofmanufacture, and not subject to change or replacement thereafter.

The battery of an implant device can begin draining after manufactureand assembly of the device. In cases where the battery is not readilyaccessible or changeable, it is necessary to maximize the shelf life ofthe battery and operational use of the implant device. Therefore, theamount of power consumed by the internal components prior to use of theimplant device needs to be minimized.

One method of reducing the amount of power consumed prior to use of thedevice is to deactivate a portion of the implant device during storageand activate the portion of the implant device shortly before use. Forexample, an implant device may be configured to detect unpacking of thepackage containing the implant device and activate the supply of powerfrom the battery only after detecting the unpacking of the package.However, this approach requires additional components to detect theunpacking of the device (such as a magnet and reed relay) and canincrease the overall unit cost of the implant device.

Another approach for restricting the amount of power consumption is todeactivate a portion of the implant device during storage andperiodically activate the portion of the implant device to detectwhether the implant device has been implanted. While this method mayeliminate the need for additional components to detect unpacking, powerfrom the battery is still consumed each time the portion of the implantdevice is activated. Therefore, this approach may require a larger andmore expensive battery to provide a sufficient power source forperiodically activating the implant device and for subsequent use afterunpacking. As a result, it may not be suitable for many applications.

Accordingly, existing systems and methods for activating an implantdevice do not address the challenge of minimizing the number ofcomponents and prolonging shelf life of the device, without increasingthe power requirements of the battery or overall expense of the device.

SUMMARY

The present disclosure generally relates to systems and methods foractivating a circuit of an implant device. As further described herein,embodiments of the present disclosure include systems and methods thatare capable of activating a circuit of an implant device uponimplantation of the device in a subject, while minimizing the number ofcomponents and power requirements of the device. Embodiments of thepresent disclosure also include systems and methods that are capable ofactivating a circuit of an implant device upon electrical coupling of asensor to the device.

In accordance with one example embodiment, an implantation detector ofan implant device is electrically coupled to a counter electrode (CE) ofa sensor. The sensor is configured to generate current at the CE whenthe implant device is implanted in a body of an individual or othersubject. The implantation detector may include a clock signal generatorthat generates a clock signal, and a switch located between the CE ofthe sensor and ground that shorts the CE with ground based on the clocksignal. The implantation detector may also include a voltage detectorthat detects a voltage at the CE of the sensor and activates a sensingcircuit for measuring a physiological parameter of the individual orother subject, the sensing circuit being electrically coupled to aworking electrode (WE) of the sensor based on the voltage at the CE ofthe sensor.

In accordance with another example embodiment, an implant device isprovided that includes a sensor with a WE and a CE. The sensor maygenerate a first current at the CE when the implant device is implantedin a body of an individual or other subject. The implant device mayfurther include a sensing circuit for measuring a physiologicalparameter of the individual or other subject, the sensing circuit beingelectrically coupled to the WE of the sensor and an implantationdetector that activates the sensing circuit based on the first current.

In accordance with yet another example embodiment, a method foractivating a circuit for measuring a physiological parameter of anindividual is provided. The method includes providing a sensor includinga WE and a CE, the WE of the sensor being electrically coupled to thesensing circuit. The method further comprises generating a first currentat the CE of the sensor in response to implantation of the implantdevice in a body of the individual and activating the sensing circuitbased on the first current in response to the generation of the firstcurrent.

In accordance with an example embodiment, an implant device is providedthat includes a sensor interface configured to interface with a sensor,and a sensing circuit that measures at least one physiological parameterof an individual. The implant device may further include a sensordetector configured to detect whether the sensor is interfacing with thesensor interface and activate the sensing circuit based on thedetection.

In accordance with another example embodiments, a method is provided foractivating a sensing circuit of an implant device for measuring at leastone physiological parameter of an individual. The method includesproviding a sensor interface that is configured to interface with asensor, detecting whether the sensor is interfacing with the sensorinterface, and activating the sensing circuit based on the detection ofwhether the sensor interfacing with the sensor interface.

Before explaining example embodiments of the present disclosure indetail, it is to be understood that the disclosure is not limited in itsapplication to the details of construction and to the arrangements ofthe components set forth in the following description or illustrated inthe drawings. The disclosure is capable of embodiments in addition tothose described and of being practiced and carried out in various ways.Also, it is to be understood that the phraseology and terminologyemployed herein, as well as in the abstract, are for the purpose ofdescription and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conceptionand features upon which this disclosure is based may readily be utilizedas a basis for designing other structures, methods, and systems forcarrying out the several purposes of the present disclosure.Furthermore, the claims should be regarded as including such equivalentconstructions insofar as they do not depart from the spirit and scope ofthe present disclosure.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are incorporated in and constitute partof this specification, and together with the description, illustrate andserve to explain the principles of various exemplary embodiments.

FIG. 1 depicts an example system environment for implementingembodiments of the present disclosure.

FIG. 2 is a cross-sectional view of an implant device implementingembodiments consistent with the present disclosure.

FIG. 3 is a graph showing a transient response of an exampleelectrochemical sensor consistent with embodiments of the presentdisclosure.

FIG. 4 is a block diagram illustrating an example implant deviceconsistent with embodiments of the present disclosure.

FIG. 5 is a circuit diagram of an example implantation detection circuitconsistent with embodiments of the present disclosure.

FIG. 6 is a flowchart of an example method consistent with embodimentsof the present disclosure.

FIG. 7 is a cross-sectional view of an implant device implementingembodiments consistent with the present disclosure.

FIG. 8 is a block diagram illustrating an example implant deviceconsistent with embodiments of the present disclosure.

FIG. 9 is a circuit diagram of an example sensor detection circuitconsistent with embodiments of the present disclosure.

FIG. 10 is a flowchart of an example method consistent with embodimentsof the present disclosure.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Embodiments of the present disclosure provide improved systems andmethods for activating a portion of an implant device with power from abattery by detecting that the implant device is implanted in the body ofa subject. The disclosed embodiments are capable of detecting that animplant device is implanted in the body of a subject, while minimizingthe number of required components and the amount of power used fordetecting the implantation.

Reference will now be made in detail to the embodiments implementedaccording to the disclosure, the examples of which are illustrated inthe accompanying drawings. Wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.

FIG. 1 depicts an example system environment 100 for implementingembodiments of the present disclosure. As shown in FIG. 1 , systemenvironment 100 includes an implant device 120. In some embodiments,implant device 120 is positioned in a subject 110. Subject 110 may be ahuman subject as shown in FIG. 1 . Alternatively, subject 110 may be ananimal subject or any other type of living subject. The size anddimensions of implant device 120 may be vary depending on the needs orparticular use(s) of the device. In some embodiments, implant device 120may be a centimeter implanted device (i.e., a device having sizedimensions at least one centimeter each), a millimeter implanted device(i.e., a device having size dimensions less than one centimeter but atleast one millimeter each), or a sub-millimeter implanted device (i.e.,a device having size dimensions less than one millimeter each).

Implant device 120 may be capable of being implanted at variouslocations and at various depths within the body of subject 110. Whileimplant device 120 is shown in FIG. 1 as being implanted in the arm ofsubject 110, other implant locations are contemplated and theillustrated example is in no way intended to be limiting on theembodiments of the present disclosure.

Implanted device 120 may measure various parameters of subject 110. Insome embodiments, implant device 120 may include a system forcontinuously measuring the glucose level of subject 110. In someembodiments, implant device 120 may further include one or moresubsystems for sensing the glucose level and/or other parameter(s) ofsubject 110, providing the measured data to an external monitoringsystem, and/or storing the measured data. In some embodiments, implantdevice 120 may further include a subsystem for interacting with anotherimplanted device. For example, implant device 120 may include asubsystem for providing the measured glucose level to another device(implanted and/or external) that delivers insulin to subject 110. Otherexample subsystems may be used in conjunction with the disclosedembodiments, however, and the enumerated examples are in no way intendedto be limiting on the scope of the present disclosure.

FIG. 2 is a cross-sectional view of an exemplary implant device 120. Asshown in FIG. 2 , implant device 120 includes a number of components. Itwill be appreciated from the present disclosure that the number andarrangement of these components is exemplary only and provided forpurposes of illustration. Other arrangements and numbers of componentsmay be utilized without departing from the teachings and embodiments ofthe present disclosure.

As shown in FIG. 2 , implant device 120 includes a battery 220, amicrochip 230, and a sensor 240, which are mounted on a substrate orcircuit board 210. In some embodiments, one or more of battery 220,microchip 230, and sensor 240 may be inside or partially inside circuitboard 210. Further, in some embodiments, circuit board 210 may includeinterconnect 225 and interconnect 235 that electrically interconnectbattery 220 to microchip 230 and microchip 230 to sensor 240,respectively. Interconnects 225 and 235 may be implemented using copperor another suitable metal layer for interconnecting the components ofimplant device 120.

In some embodiments, sensor 240 may be implemented as an electrochemicalsensor. Electrochemical sensors operate by reacting with the stimuli ofinterest (i.e., “analyte”) and producing an electrical signalproportional to the concentration of the analyte. The analyte may reactat the surfaces of a working electrode (WE) and/or a counter electrode(CE) involving either an oxidation and/or reduction mechanism. Thesereactions may be catalyzed by the electrode materials specificallydeveloped for the analyte.

In some embodiments, when sensor 240 becomes in contact with the analytefor the first time (e.g., when the sensor is first implanted in the bodyof subject 110), a large, amperometric current may be initially drawn orgenerated at the WE and CE of the sensor, for example, due toinstantaneous reduction of oxygen at the surface of the CE and/oroxidation at the surface of the WE. As the electrochemical reactionscontinue, however, the amperometric current decreases to a steady-staterange that is approximately proportional to the analyte concentration atthe electrodes.

Microchip 230 may be, for example, an application-specific integratedcircuit (ASIC) or any other component(s) containing electronic circuits(e.g., discrete circuit elements and field-programmable gate array(FPGA)). In some embodiments, implant device 120 may further includesealant 250 encapsulating battery 220 and/or microchip 230 so as toprevent the components from becoming in direct contact with the body ofsubject 110. In some embodiments, sealant 250 may be a hermetic sealant.In some embodiments, microchip 230 may include a plurality of chips.

A portion of microchip 230 may be deactivated before implant device 120is implanted in the body of subject 110 to maximize the shelf life ofimplant device 120. In one example, the portion comprises one or morecircuit components of microchip 230 that are deactivated by preventingpower from being supplied to them while microchip 230 is stored or notused. The deactivated portion of microchip 230 may be activated afterdetecting that implant device 120 has been implanted in the body ofsubject 110. In some embodiments, microchip 230 may be configured todetect the implantation of implant device 120 in the body of subject 110by, for example, including a circuit to detect the large, initial,amperometric current generated at the CE of electrochemical sensor 240immediately after sensor 240 first comes into contact with the body ofsubject 110.

FIG. 3 is a graph 300 showing a transient response of exampleelectrochemical sensor 240 of FIG. 2 , consistent with embodiments ofthe present disclosure. The dependent variable (y-axis) of graph 300 isthe amount of current drawn/generated by sensor 240, for example, innano-amps, and the independent variable (x-axis) of graph 300 is time,for example, in seconds.

At time t₁, implant device 120 including sensor 240 is implanted in thebody of subject 110. Thus, the time period before t₁ represents a periodbefore implant device 120 is implanted in the body of subject 110.Before t₁, sensor 240 may generate no current or a negligible amount ofcurrent. Immediately after t₁ (i.e., immediately after implantation),however, sensor 240 may generate a large, initial, amperometric current.In the example of FIG. 3 , electrochemical sensor 240 generates over 100nA immediately after implant device 120 is implanted in the body ofsubject 110.

At time t₂, which is at a predetermined amount time after t₁, thecurrent generated by sensor 240 may decrease to a steady-state range. Inthe example of FIG. 3 , t₂ may be 200 seconds after t₁, and thesteady-state current range may be between 1 nA and 5 nA, for example.After t₂, the current drawn/generated by sensor 240 may be proportionalto the analyte concentration (e.g., glucose concentration). A skilledartesian may experimentally determine time t₂ for a given sensor, forexample, based on a graph similar to graph 300.

FIG. 4 is a block diagram illustrating a portion of example implantdevice 120 shown in FIG. 2 , consistent with embodiments of the presentdisclosure. In FIG. 4 , electrochemical sensor 240 of implant device 120includes a working electrode (WE) connected to a WE node 240A and acounter-electrode (CE) connected to a CE node 240B. In some embodiments,electrochemical sensor 240 may further include a reference electrode(RE).

In FIG. 4 , microchip 230 may include a sensing circuit 410 formeasuring one or more physiological parameter of an individual and animplantation detector circuit 420 for detecting implantation of theimplant device in a body of the individual. In the example implantdevice 120 of FIG. 4 , sensing circuit 410 and implantation detectioncircuit 420 both use a single or common sensor (e.g., electrochemicalsensor 240) for measuring one or more physiological parameters of theindividual and for detecting implantation of the implant device in thebody of the individual.

In alternative embodiments, implant device 120 may include a firstsensor for detecting implantation of implant device 120 in a body of anindividual and a second sensor for measuring one or more physiologicalparameter of the individual. In these embodiments, sensing circuit 410may measure one or more physiological parameters of the individual usingthe first sensor and implantation detection circuit 420 may use thesecond sensor to detect implantation of the implant device in a body ofthe individual. In these embodiments, the first and second sensors maybe different type of sensors. For example, the second sensor may be anelectrochemical sensor configured to detect one type of physiologicalparameter(s), while the first sensor is another electrochemical sensorconfigured to detect another type of physiological parameter(s).

In some embodiments, sensing circuit 410 may measure one or morephysiological parameters of the individual using both the first andsecond sensors. For example, the first and second sensors may beconfigured to measure the same physiological parameters, and sensingcircuit 410 may obtain a more accurate measurement by using both sensorscompared to an embodiment using a single circuit. In another example,the first and second sensors may be configured to measure differentphysiological parameters, and sensing circuit 410 may measure aplurality of physiological parameters using the first and secondsensors.

In some embodiments, sensing circuit 410 may be electrically connectedto implantation detector circuit 420, for example, via an interconnect430. Sensing circuit 410 and/or implantation detector circuit 420 may beelectrically connected to and powered by battery 220. In someembodiments, microchip 230 may include a first chip including sensingcircuit 410 and a second chip including implantation detector circuit420.

In some embodiments, sensing circuit 410 may operate in one of at leasttwo modes. In a first mode, sensing circuit 410 may be configured toconsume zero or substantially zero power from a power source such asbattery 220. In FIG. 4 , for example, sensing circuit 410 includes oneor more switches 414 between one or more portions 412 of sensing circuit410 and battery 220. Switches 414 may be configured to create an openconnection (i.e., preventing current from flowing) between portions 412and battery 220 while sensing circuit 410 is in the first mode.

In some embodiments, portions 412 of sensing circuit 410 may include ananalog-to-digital converter (ADC) arranged to convert the amount ofcurrent generated at WE node 240A to a digital signal. Additionally, oralternatively, portions 412 of sensing circuit 410 may include anamplifier (e.g., transimpedence amplifier) for generating avoltage-based signal, or a current-based signal having a largeramplitude compared to the raw signal generated by sensor 240.Furthermore, portions 412 of sensing circuit 410 may include a circuitthat generates a voltage-based or current-based signal having adifferent output impedance. Portions 412 of sensing circuit 410 mayfurther include other circuit(s) for accurately measuring the currentgenerated at WE node 240A.

In a second mode, sensing circuit 410 may be configured to consumesufficient power necessary to sense the current drawn at WE of sensor240 (i.e. at WE node 240A). For example, in exemplary implant device 120of FIG. 4 , switches 414 may create a closed connection (i.e., allowingcurrent to flow) between portion 412 and battery 220 while sensingcircuit 410 is in the second mode. Therefore, the amount of powerconsumed by sensing circuit 410 in the second mode may be greater thanthe amount of power consumed by sensing circuit in the first mode.

In some embodiments, the operating mode of sensing circuit 410 may bedetermined based on an electrical signal from implantation detectioncircuit 420. For example, a first signal from implantation detectioncircuit 420 via interconnect 430 may cause sensing circuit 410 tooperate in the first mode while a second signal from implantationdetection circuit 420 via interconnect 430 may cause sensing circuit 410to operate in the second mode. In this example, interconnect 430 may becoupled to switches 414 to control the supply of power from battery 220to portions 412 of sensing circuit 410.

In some embodiments, sensing circuit 410 may switch between one mode toanother mode no more than a predetermined number of times. For example,sensing circuit 410 may switch from the first mode to the second mode nomore than once, based on an electrical signal from implantationdetection circuit 420. In this example, after switching to the secondmode, sensing circuit 410 may remain in the second mode irrespective ofthe electrical signal received from implantation detection circuit 420.

It will be appreciated that a circuit element may be a linear or anonlinear element, such as, but not limited to, a resistor, a capacitor,an inductor, a transistor, a memristor, a diode, a transistor, a switch,a current/voltage source, to provide some examples.

In FIG. 4 , WE node 240A is shown to be connected to sensing circuit 310only; however, it will be appreciated that WE node 240A may be connectedto additional circuits including, for example, a circuit providing abias voltage between WE node 240A and ground. In one example, the biasvoltage between the WE and the CE may be 0.5 V.

Further as noted above, the CE of electrochemical sensor 240 maygenerate a large, initial, amperometric current immediately afterelectrochemical sensor 240 first comes into contact with the body ofsubject 110. Implantation detection circuit 420 may detect suchamperometric current. For example, implantation detection circuit 420may include one or more circuit elements arranged to generate a firstsignal (e.g., at interconnect 430) when zero current or substantiallyzero current is detected at the CE node 240B and generate a secondsignal (e.g., at interconnect 430) when current above/below apredetermined, threshold current is detected at the CE node 240B. Thethreshold current may be set based on the expected initial, amperometriccurrent generated by the electrochemical sensor being used. For example,it will be appreciated by a skilled artisan that the threshold currentmay be determined by experimentally obtaining a graph of a transientresponse for the electrochemical sensor being used, similar to graph 300of FIG. 3 .

FIG. 5 is a circuit diagram of an example implantation detection circuit420 shown in FIG. 4 , consistent with embodiments of the presentdisclosure. As disclosed herein, implantation detection circuit 420 maygenerate a first signal before implant device 120 is implanted and asecond signal after implant device 120 is implanted. The generatedsignal, as noted above, may be used by sensing circuit 410 to determinethe mode of operation. For example, the first signal generated byimplantation detection circuit 420 may cause sensing circuit 410 tooperate in a first mode while a second signal generated by implantationdetection circuit 420 may cause sensing circuit 410 to operate in asecond mode.

Example implantation detection circuit 420 of FIG. 5 includes acapacitor 510 between CE node 240B and ground. Capacitor 510 is alsoarranged to store charges generated at CE node 240B. Implantationdetection circuit 420 further includes a switch 520 (e.g., a relay)between CE node 240B and ground. In some embodiments, switch 520 mayperiodically short CE node 240B to ground. For example, switch 520 maybe configured to close or open in response to a signal generated by aclock circuit 530. The periodic shorting of CE node 240B to ground mayperiodically drain the charges stored by capacitor 510. Therefore, theaverage amount of current generated at CE node 240B may determine themaximum amount of charge stored in capacitor 150 as well as the maximumvoltage between CE node 240B and ground during a single clock cycle.

Example implantation detection circuit 420 of FIG. 5 further includes athreshold detector 540 that generates an output signal based on thedetected voltage between CE node 240B and ground. For example, thresholddetector 540 may output a first signal when the voltage between CE node240B and ground is below a threshold voltage and output a second signalonce the voltage between CE node 240B and ground is above (or equal to)the threshold voltage. In some embodiments, threshold detector 540 maycontinue to generate the second signal even when the voltage between CEnode 240B and ground subsequently falls below the threshold voltage.

In some embodiments, once threshold detector 540 detects a voltage thatis above the threshold voltage, threshold detector 540 may cause switch520 to close permanently thereby permanently shorting the CE node 240Bwith ground.

In some embodiments, the first signal and the second signal may berepresented by one or more voltage or current levels. For example, thefirst signal may be represented by the supply voltage of microchip 230,while the second single may be represented by the ground-level voltage.

In some embodiments, the capacitance of capacitor 510 may be between 10nF and 500nF, the frequency of the signal generated by clock circuit 530may be between 10 Hz and 100 Hz, and/or the threshold voltage of voltagethreshold detector 440 may be between 50 m V and 1 V.

FIG. 6 is an illustrative process 6000 for activating a circuit formeasuring one or more physiological parameters of an individual. At step6010, a sensor including a WE and a CE is provided. In some embodiments,the WE of the sensor may be electrically coupled to a sensing circuit.At step 6020, a first current is generated at the CE of the sensor inresponse to implantation of the implant device in a body of theindividual. At step 6030, the sensing circuit is activated in responseto the generation of the first current. In some embodiments, theactivation of the sensing circuit in response to the first current mayinclude generating a clock signal, shorting the CE with ground based onthe clock signal, detecting a voltage between the CE of the sensor andground, and activating the sensing circuit based on the voltage betweenthe CE of the sensor and ground. In some embodiments, the activation ofthe sensing circuit may further include providing power from a powersource to activate the sensing circuit. In some embodiments, the powersource may be a battery. At step 6040, the activated sensing circuit maymeasure one or more physiological parameters of the individual.

FIG. 7 is a cross-sectional view of another exemplary implant device700. As shown in FIG. 7 , implant device 700 includes a battery 720 anda microchip 730, which are mounted on a substrate or circuit board 710.Circuit board 710 may include interconnect 725 that electricallyinterconnects battery 720 to microchip 730. Circuit board 710 may alsoinclude interconnect 735 that is electrically connected to microchip730.

Microchip 730 may be, for example, an ASIC or any other component(s)containing electronic circuits (e.g., discrete circuit elements andFPGA). In some embodiments, implant device 700 may further includesealant 750 encapsulating battery 720 and/or microchip 730 so as toprevent the components from becoming in direct contact with the body ofsubject 110. In some embodiments, sealant 750 may be a hermetic sealant.In some embodiments, microchip 730 may include a plurality of chips.

FIG. 7 also shows a sensor 740. However, unlike sensor 240 of implantdevice 120 of FIG. 2 , which may be assembled to substrate 210 duringthe manufacturing process, sensor 740 may be separate from implantdevice 700 even after the manufacturing process. In some embodiments,sensor 740 and implant device 700 may be configured such that sensor 740may be assembled to circuit board 710 after the manufacturing process(e.g., by the patient or physician). For example, as shown in FIG. 7 ,implant device 700 may include a sensor interface 745 that electricallycouples sensor 740 with microchip 730 (via interconnect 735). Further,sensor interface 745 may be configured to facilitate electrical couplingof microchip 730 with sensor 740 after the manufacturing process. Forexample, sensor interface 745 may be an array of exposed I/O pads thatcan align and bond to an array of solder balls I/Os of sensor 740.

In some embodiments, sensor interface 745 may be configured such thatsensor 740 can be electrically coupled to microchip 730 without toolssuch as soldering tools, alignment tools, and/or reflow heaters. Forexample, sensor interface 745 may be a socket-based or slot-basedinterface that is compatible with electrical interfaces of sensor 740.These interfaces may be used to electrically couple sensor 740 withmicrochip 730 at the user end (e.g., by the patient, physician, orsalesperson).

In some embodiments, sensor interface 745 may be a re-matable interfacewhere sensor 740 can repeatedly de-interface or re-interface with sensorinterface 745. Additionally, or alternatively, sensor interface 745 mayfacilitate repeated electrical coupling and decoupling of sensor 740with microchip 730. In some embodiments, sensor interface 745 mayinclude a mechanism to hold sensor 740 to circuit board 710. Forexample, sensor interface 745 may include a mechanical clamp to holdsensor 740 to circuit board 710.

Sensor interface 745 may include an electrical interface to facilitateelectrical coupling of sensor 740 with microchip 730 via interconnect735. In some embodiments, the electrical interface may be a capacitive,resistive, and/or inductive interface.

Sensor 740 may be an electrochemical sensor, an inertial sensor,pressure sensor, light sensor, microphone, or any other sensor that canbe implanted to subject 110.

A portion of microchip 730 may be deactivated while sensor 740 isseparate from implant device 700 (i.e., while sensor 740 is electricallydecoupled from microchip 730 and/or de-interfaced from sensor interface745) to maximize the shelf life of implant device 700. In one example,the portion comprises one or more circuit components of microchip 730that are deactivated by preventing power from being supplied to themwhile sensor 740 is separate from implant device 700. The deactivatedportion of microchip 730 may be activated after detecting that sensor740 has interfaced with sensor interface 745 and/or electrically coupledto microchip 730.

FIG. 8 is a block diagram illustrating a portion of example implantdevice 700 shown in FIG. 7 , consistent with embodiments of the presentdisclosure. In FIG. 8 , sensor 740 of implant device 700 includes afirst electrode connected to a first node 740A and a second electrodeconnected to a second node 740B.

In FIG. 8 , microchip 730 may include a sensing circuit 810 formeasuring one or more physiological parameter of an individual, and asensor detector circuit 820 for detecting when sensor 740 interfaceswith sensor interface 745 and/or when sensor 740 electrically coupleswith microchip 730. As shown in FIG. 8 , first node 740A and second node740B are connected to sensor detection circuit 820 and at least firstnode 740A is connected to sensing circuit 810. In some embodiments,second node 740B may also be connected to sensing circuit 810.

In some embodiments, sensing circuit 810 may be electrically connectedto sensor detector circuit 820, for example, via an interconnect 830.Sensing circuit 810 and/or sensor detector circuit 820 may beelectrically connected to and powered by battery 720. In someembodiments, microchip 730 may include a first chip including sensingcircuit 810 and a second chip including sensor detector circuit 820.

In some embodiments, portions 812 of sensing circuit 810 may include ananalog-to-digital converter (ADC) arranged to convert the current orvoltage levels (or potential) at first node 740A to a digital signal.Additionally, or alternatively, portions 812 of sensing circuit 810 mayinclude an amplifier (e.g., a transimpedence amplifier) for generating avoltage-based signal, or a current-based signal having a largeramplitude compared to the raw signal sensed at first node 740A.Furthermore, portions 812 of sensing circuit 810 may include a circuitthat generates a voltage-or current-based signal having a differentoutput impedance. Portion 812 of sensing circuit 810 may further includeother circuit(s) for accurately measuring the current or voltage atfirst node 740A. In some embodiments, portions 812 of sensing circuit810 may also connect to second node 740B. In these embodiments, portions812 of sensing circuit 810 may further includes circuit(s) foraccurately measuring the current or voltage at second node 740B.

In some embodiments, sensing circuit 810 may operate in one of at leasttwo modes. In a first mode, sensing circuit 810 may be configured toconsume zero or substantially zero power from a power source such asbattery 720. In FIG. 8 , for example, sensing circuit 810 includes oneor more switches 814 between one or more portions 812 of sensing circuit810 and battery 720. Switches 814 may be configured to create an openconnection (i.e., preventing current from flowing) between portions 812and battery 720 while sensing circuit 810 is in the first mode.

In a second mode, sensing circuit 810 may be configured to consume asufficient power necessary to sense the current or voltage at first node740A (and/or second node 740B). For example, in exemplary implant device700 of FIG. 8 , switches 814 may create a closed connection (i.e.,allowing current to flow) between portion 812 and battery 720 whilesensing circuit 810 is in the second mode. Therefore, the amount ofpower consumed by sensing circuit 810 in the second mode may be greaterthan the amount of power consumed by sensing circuit in the first mode.

In some embodiments, the operating mode of sensing circuit 810 may bedetermined based on an electrical signal from sensor detection circuit820. For example, a first signal from sensor detection circuit 820 viainterconnect 830 may cause sensing circuit 810 to operate in the firstmode while a second signal from sensor detection circuit 820 viainterconnect 830 may cause sensing circuit 810 to operate in the secondmode. In this example, interconnect 830 may be coupled to switches 814to control the supply of power from battery 820 to portions 812 ofsensing circuit 810.

In some embodiments, while in the first mode and/or second mode,portions 812 of sensing circuit 810 may be configured to such that aninput impedance is high (e.g., similar to an input impedance of anop-amp) so as to maximize the portion of current flowing to sensordetection circuit 820.

In some embodiments, sensor 740 may be configured to electrically couplethe first and second electrodes. For example, sensor 740 mayresistively, capacitive, and/or inductively couple the first and secondelectrodes of sensor 740. In these embodiments, when a signal is presentat the second electrode of sensor 740, a corresponding signal that isbased on the signal may be generated at the first electrode of sensor740.

It will be appreciated that a circuit element may be a linear or anonlinear element, such as, but not limited to, a resistor, a capacitor,an inductor, a transistor, a memristor, a diode, a transistor, a switch,a current/voltage source, to provide some examples.

FIG. 9 is a circuit diagram of an example sensor detection circuit 820shown in FIG. 8 , consistent with embodiments of the present disclosure.As disclosed herein, sensor detection circuit 820 may generate a firstsignal at interconnect 830 when sensor detection circuit 820 detectsthat sensor 740 is electrically decoupled from microchip 730 and asecond signal at interconnect 830 when sensor detection circuit 820detects that sensor 740 is electrically coupled with microchip 730. Thegenerated signal, as noted above, may be used by sensing circuit 810 todetermine the mode of operation. For example, the first signal generatedby sensor detection circuit 820 may cause sensing circuit 810 to operatein a first mode while a second signal generated by sensor detectioncircuit 820 may cause sensing circuit 810 to operate in a second mode.

As shown in FIG. 9 , sensor detection circuit 820 includes a signalgenerator 930 connected to second node 740B. In some embodiments, signalgenerator 930 may generate a voltage-based or a current based signal atsecond node 740B. In some embodiments, the signal generated by signalgenerator 930 may be an AC signal (voltage or current). Alternatively,the signal generated by signal generator 930 may be a DC voltage or DCcurrent. In some embodiments, the signal generator may be a clock signalgenerator.

In some embodiments, as shown in FIG. 9 , sensor detection circuit 820may further include a switch 920 between second node 740B and ground.While sensing circuit 810 is in the first mode, switch 920 may be opensuch the voltage or current at second node 740B is the signal fromsignal generator 930. In some embodiments, however, while sensingcircuit 810 is in the second mode, switch 920 may be closed such thatsecond node 740 is electrically shorted to ground. That is, whilesensing circuit 810 is in the second mode, second node 740B may begrounded even when signal generator 930 generates a signal. Thegrounding of second node 740B may increase the accuracy of sensingcircuit 810.

As shown in FIG. 9 , sensor detector circuit 820 may also include asignal detector 940 connected to first node 740A. Signal detector 940may be configured to sense (or measure) voltage and/or current levels atfirst node 740A. Further, based on the sensed levels, signal detector940 may generate the first or second signal at interconnect 830. Thisgenerated signal, as noted above, may be used by sensing circuit 810 todetermine the mode of operation.

In some embodiments, the first signal and the second signal may berepresented by one or more voltage or current levels. For example, thefirst signal may be represented by the supply voltage of microchip 730,while the second single may be represented by the ground-level voltage.

As discussed above, in some embodiments, sensor 740 may be configured toelectrically couple the first and second electrodes. Further asdiscussed above, in these embodiments, when a signal is present at thesecond electrode of sensor 740, a corresponding signal that is based onthe signal may be generated at the first electrode of sensor 740. Insome embodiments, when sensor 740 interfaces with sensor interface 745,the first electrode of sensor 740 may electrically couple with firstnode 740A and the second electrode of sensor 740 may electrically couplewith second node 740B. Therefore, when sensor 740 electrically couplesto microchip 730, the signal generated by signal generator 930 at secondnode 740B may cause a corresponding signal to be generated at first node740A (since sensor 740 may electrically couple first node 740A withsecond node 740B).

In some embodiments, sensor detector circuit 820 may determine thatsensor 740 is electrically coupled to microchip 730 when thecorresponding signal is detected at first node 740A. Further, sensordetector circuit 940 may determine that sensor 740 is electricallydecoupled from microchip 730 when the corresponding signal is notdetected at first node 740A. In some embodiments, the correspondingsignal may be derived from the generated signal. Alternatively, oradditionally, the corresponding signal may be substantially the same asthe generated signal.

In one example, sensor 740 may be configured to capacitively couple thefirst and second electrodes of sensor 740. And, when sensor 740interfaces with sensor interface 745, the first electrode of sensor 740may electrically couple with first node 740A and the second electrode ofsensor 740 may electrically couple with the second node 740B. Therefore,in this example, when signal generator 930 generates a first AC voltagesignal having a first frequency at second node 740B, a second AC voltagesignal may be generated at first node 740A since first node 740A andsecond node 740B are capacitively coupled via sensor 740. Further, thesecond AC voltage signal may have the same frequency as the first ACvoltage signal.

Additionally, sensor detector circuit 940 may determine that sensor 740is electrically decoupled with microchip 730 when an AC voltage signalhaving the same frequency is not detected at first node 740A, anddetermine that sensor 740 is electrically coupled with microchip 730when an AC voltage signal having the same frequency is detected at firstnode 740A.

In some embodiments, sensor detector circuit 940 may include a thresholddetector that generates an output signal based on the detected voltageor current at first node 740A. For example, the threshold detector ofsensor detector circuit 940 may output a first signal at interconnect830 when the voltage at first node 740A is below a threshold voltage orcurrent and output a second signal once the voltage at first node 740Ais above (or equal to) the threshold voltage.

In one example, sensor 740 may be configured to resistively couple thefirst electrode and the second electrode of sensor 740. Further, signalgenerator 930 may generate a first DC voltage-level (e.g., positivevoltage) at second node 740B. When sensor 740 is electrically coupled tomicrochip 730, a second DC voltage level may be generated at first node740A because first node 740A and second node 740B are resistivelycoupled via sensor 740. Further, the second DC voltage level may belower than the first DC voltage level. In this example, the thresholddetector of sensor detector circuit 940 may determine that sensor 740 iselectrically decoupled from microchip 730 when a voltage level detectedat first node 740A is below a threshold voltage, and determine thatsensor 740 is electrically coupled to microchip 730 when a voltage leveldetected at first node 740A is above the threshold voltage.

In some embodiments, the threshold detector of sensor detector circuit940 may determine that sensor 740 is electrically decoupled to microchip730 when a voltage level detected at first node 740A is below a firstthreshold voltage, and determine that sensor 740 is electrically coupledto microchip 730 when a voltage level detected at first node 740A isabove a second threshold voltage. In these embodiments, the first andsecond threshold voltages may be different.

FIG. 10 is an illustrative process 10000 for activating a sensingcircuit of an implant device for measure at least one physiologicalparameter of an individual using the sensor. At step 10010, a sensorinterface for interfacing with a sensor is provided. At step 10020, asensor detector may detect whether the sensor is interfacing with thesensor interface. At step 10030, the sensor detector may activate thesensing circuit based on the detection of whether the sensor interfacingwith the sensor interface.

At an optional step, the sensor interface may interface the sensor. Insome embodiments, the interfacing of the sensor interface with thesensor may include mechanically holding the sensor to the implantdevice. In some embodiments, the interfacing of the sensor interfacewith the sensor may include electrically coupling the sensor interfacewith the sensor. In some embodiments, the detection of whether thesensor is interfacing with the sensor interface may include sending asignal to the sensor interface and receiving a corresponding signal fromthe sensor interface when the sensor is interfacing with the sensorinterface. In these embodiments, the corresponding signal is related tothe signal. In some embodiments, the signal and the corresponding signalmay have the same frequency. At an optional step, a sensing circuit,using the sensor, may measure the at least one physiological parameterof the individual after the interfacing of the sensor interface with thesensor. At an optional step, the sensor may de-interface the sensorinterface re-interfacing the sensor interface.

In the preceding specification, various exemplary embodiments andfeatures have been described with reference to the accompanyingdrawings. It will, however, be evident that various modifications andchanges may be made thereto, and additional embodiments and features maybe implemented, without departing from the broader scope of theinvention as set forth in the claims that follow. For example,advantageous results still could be if components in the disclosedsystems were combined in a different manner and/or replaced orsupplemented by other components. Other implementations are also withinthe scope of the following exemplary claims. The specification anddrawings are accordingly to be regarded in an illustrative rather thanrestrictive sense. Moreover, it is intended that the disclosedembodiments and examples be considered as exemplary only, with a truescope of the present disclosure being indicated by the following claimsand their equivalents.

1. A method for activating a sensing circuit for measuring at least onephysiological parameter of an individual, the method comprising:providing a sensor including a working electrode (WE) and a counterelectrode (CE), the WE of the sensor being electrically coupled to thesensing circuit; generating a first current at the CE of the sensor inresponse to insertion of the sensor into a body of the individual; andactivating the sensing circuit based on the first current in response tothe generation of the first current.
 2. The method of claim 1, whereinactivation of the sensing circuit based on the first current includes:generating a clock signal; shorting the CE with ground based on theclock signal; detecting a voltage between the CE of the sensor andground; and activating the sensing circuit based on the voltage betweenthe CE of the sensor and ground.
 3. The method of claim 2, wherein theactivation of the sensing circuit based on the voltage between the CE ofthe sensor and ground includes providing power from a power source toactivate the sensing circuit.
 4. The method of claim 1, wherein thesensor is an electrochemical sensor.
 5. The method of claim 1, furthercomprising measuring, using the activated sensing circuit, the at leastone physiological parameter of the individual.
 6. The method of claim 1,wherein the at least one physiological parameter of the individual is aglucose level.
 7. The method of claim 1, wherein the sensing circuit iscontained within a sensor device, and further comprising implanting thesensor device in the body of the individual.
 8. The method of claim 1,further comprising applying a bias voltage to the WE.
 9. A sensor devicecomprising: a power source; a sensing circuit configured to measure atleast one physiological parameter of an individual; an insertiondetection circuit; and a sensor comprising a working electrode (WE) anda counter electrode (CE), the WE of the sensor being electricallycoupled to the sensing circuit and the insertion detection circuit,wherein the insertion detection circuit is configured to activate thesensing circuit in response to insertion of the sensor into a body ofthe individual.
 10. The sensor device of claim 9, wherein insertiondetection circuit is configured to: generate a clock signal; short theCE with ground based on the clock signal; detect a voltage between theCE of the sensor and ground; and activate the sensing circuit based onthe voltage between the CE of the sensor and ground.
 11. The sensordevice of claim 9, wherein insertion detection circuit is configured todetect an amperometric current in response to the insertion of thesensor into the body of the individual.
 12. The sensor device of claim11, wherein the insertion detection circuit is further configured tocompare the amperometric current to a threshold.
 13. The sensor deviceof claim 9, wherein insertion detection circuit is configured to providepower from the power source to the sensing circuit in response toinsertion of the sensor into the body of the individual.
 14. The sensordevice of claim 9, wherein the sensing circuit is configured to measurethe at least one physiological parameter of the individual.
 15. Thesensor device of claim 14, wherein the at least one physiologicalparameter of the individual is a glucose level.
 16. The sensor device ofclaim 9, further comprising a microchip, wherein the microchip comprisesthe sensing circuit and the implant detection circuit.
 17. The sensordevice of claim 9, wherein the sensor is an electrochemical sensor. 18.The sensor device of claim 9, further comprising a bias circuitconfigured to apply a bias voltage to the WE.
 19. The sensor device ofclaim 18, wherein the bias circuit is configured to apply the biasvoltage between the WE and an electrical ground.
 20. The sensor deviceof claim 18, wherein the bias circuit is configured to apply the biasvoltage between the WE and the CE.